1. Field of the Invention
The present invention relates, in general, to a method, apparatus and computer program for processing multimedia data signals.
2. Description of the Related Art
Since the beginning of the digital era, there has been a demand for devices that can simultaneously receive a variety of broadcasting signals and process multimedia data such as IEEE1394 data, universal serial bus (USB) data, national renewable security system (NRSS) data, and personal video recording (PVR) data. Also, since these broadcasting signals and multimedia data are in digital form, they may be susceptible to illegal copying, with the popularity and improvement of the Internet. Accordingly, conditional access/content protection of such data is desired.
In conventional multiple multimedia data signal receiving and recording devices, encrypted digital multimedia signals may be decrypted by several conditional access (CA) units, so that the decrypted content within the signal (a signal is sometimes referred to as a stream) may be viewed on a suitable display such as a digital television. In a case where delayed access (i.e., time shifting) is required, the decrypted content may be recorded in a recording medium and then can be viewed at a later time.
However, if multiple data streams (or signals) are input, conventional receive and record devices can process only a limited number of inputs. In a case of delayed access or recording, since data is not encrypted, problems such as illegal copying may occur. Also, since the size of a buffer which receives external digital multimedia data signals and stores the data may be typically fixed, if the buffer is full, data may be lost. Furthermore, since direct memory access (DMA) is required to directly select an input/output (IO) device when data is recorded, the IO device may have substantial communication overhead.